Fixed fetal heart rate pattern after intrauterine accidental decerebration.

A fixed fetal heart rate (FHR) pattern, with a normal frequency without accelerations and decelerations can be observed in early pregnancy during the inactive episodes of the rest-activity cycle, in association with certain drugs administered to the mother and in some cases of anencephaly. In the present case report a fetus is described in which a persistent fixed FHR pattern was indicative of decerebration in utero. The latter occurred after a serious maternal respiratory and cardiovascular collapse. The discrepancy between maternal and fetal outcome and the pathophysiologic backgrounds underlying the FHR changes are discussed.